package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IUserInfoService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.io.IOException;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 * 超卖超卖问题：最开始解决方案：
 *     1.先去查询，再去修改，这是两个步骤，导致出现多线程问题，所以采用lua脚本保证原子性（可以对整个操作进行加锁，但是性能不好）
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private IUserInfoService iUserInfoService;

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private IVoucherOrderService proxy;


    //使用的jvm内存  内存限制    宕机：-》数据安全
    //无法避免消息丢失
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
//        System.out.println("执行init");
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
    }
/*    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while (true) {
                //1.获取队列中的订单信息
//                获取和删除该队列的头部，如果需要则等待直到元素可用。
                try {
                    VoucherOrder voucherOrder =  orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder (voucherOrder);
                } catch (InterruptedException e) {
                    log.info("处理订单异常", e);
                }


            }
        }
    }*/
    //redis 消息队列
    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                //1.获取消息队列中的订单信息
//                XREADGROUPGROUP gl cl COUNT 1 BLOCK 2000 STREANS streams.order >
                List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                        Consumer.from("g1", "c1"),
                                        //每次读一个          没有消息就阻塞2秒
                        StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                                            //结束标识                  >
                        StreamOffset.create(queueName, ReadOffset.lastConsumed())
                );
                //2.判断消息是否获取成功
                if (list == null || list.isEmpty()) {
                    //2.1如果获取失败，说明没有消息
//                    System.out.println("为空，继续循环");
                    continue;
                }
                //3.解析消息的订单信息
                MapRecord<String, Object, Object> record =  list.get(0);
                Map<Object, Object> values = record.getValue();
                VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                //4.如果获取成功，可以下单
                handleVoucherOrder (voucherOrder);
                //5.ACK确认 SACK stream.order g1 id
                stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.info("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                //1.获取pending-list中的订单信息
//                XREADGROUPGROUP gl cl COUNT 1 BLOCK 2000 STREANS streams.order 0
                List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                        Consumer.from("g1", "c1"),
                        StreamReadOptions.empty().count(1),
                        StreamOffset.create(queueName, ReadOffset.from("0"))
                );
                //2.判断消息是否获取成功
                if (list == null || list.isEmpty()) {
                    //2.1如果获取失败，说明pending-list没有消息 继续下一次循环
                    continue;
                }
                //3.解析消息的订单信息
                MapRecord<String, Object, Object> record =  list.get(0);
                Map<Object, Object> values = record.getValue();
                VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                try {

                    //4.如果获取成功，可以下单
                    handleVoucherOrder (voucherOrder);
                    //5.ACK确认 SACK stream.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.info("处理pending-list异常", e);
                    //handlePendingList(); 不用递归了，他会一直while true
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }

                }
            }
        }
    }



//    @Autowired
//    private VoucherOrderServiceImpl voucherOrderServiceImpl;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //2.1 订单ID
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1不为0 代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        //获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3. 返回订单id
        return Result.ok(orderId);
    }

/*    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1不为0 代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2为0 有购买资格 把下单信息保存到阻塞队列
        //2.创建订单
        VoucherOrder voucherOrder =  new VoucherOrder();
        //2.1 订单ID
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.2 用户ID
        Long userID = UserHolder.getUser().getId();
        voucherOrder.setUserId(userID);
        //2.3 代金券ID
        voucherOrder.setVoucherId(voucherId);
        //2.4放入阻塞队列
        orderTasks.add(voucherOrder);
        //获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3. 返回订单id
        return Result.ok(0);
    }*/
//


    //    @Autowired
//    private VoucherOrderServiceImpl voucherOrderServiceImpl;
//
//voucherOrderServiceImpl.createOrder(voucherId);
    @Transactional(rollbackFor = Exception.class)
    public void createVoucherOrder(VoucherOrder voucherOrder) {

        //一人一单
//        Long userId = UserHolder.getUser().getId();
        Long userId = voucherOrder.getUserId() ;
        //查询订单
//        synchronized (userId.toString().intern()) {
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次！");
            return ;
        }

        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id",voucherOrder.getVoucherId())
                .gt("stock",0) //where id = ? > 0 //乐观锁
                .update();
        if(!success){
            //扣减失败
            log.error("库存不足！");
            return;
        }
//        //6.创建订单
//        VoucherOrder voucherOrder =  new VoucherOrder();
//        //6.1 订单ID
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //6.2 用户ID
//        Long userID = UserHolder.getUser().getId();
//        voucherOrder.setUserId(userID);
//        //6.3 代金券ID
//        voucherOrder.setVoucherId(voucherOrder);
        save(voucherOrder);
        //7.返回订单ID
//        return Result.ok(voucherOrder);
//        }

    }

    @Override
//    @Transactional
    public void updateVoucher(int stock) {
        method1();
        method2();
        iUserInfoService.updateInfo();

//        int i = 1 / 0;
    }
//    @Transactional
    public void method1() {
        boolean success = seckillVoucherService.update()
                .setSql("stock = 22")
                .eq("voucher_id", 2)
                .update();
//        int i = 1 / 0;
    }

//    @Transactional
    public void method2() {
        boolean success = seckillVoucherService.update()
                .setSql("stock = 33")
                .eq("voucher_id", 10)
                .update();
//        int i = 1 / 0;
    }

    //子线程
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId() ;
        //创建锁对象  兜底 其实可以不创建锁了
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            //获取锁失败 返回错误或重试
            //单人能请求能高并发，则直接提示错误，不用让他重试了
            log.info("不允许重复下单");
            return ;
        }

        //查询订单
//        synchronized (userId.toString().intern()) {
        try{

            proxy.createVoucherOrder(voucherOrder);
        }finally {
            //释放锁
            lock.unlock();
        }
//            return voucherOrderServiceImpl.createVoucherOrder(voucherId);

//        }
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始！");
//        }
//        //3.判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束！");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足！");
//        }
//
//
//        Long userId = UserHolder.getUser().getId();
//
//        //创建锁对象
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        boolean isLock = lock.tryLock(1200);
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lick:order:" + userId);
////        boolean isLock = lock.tryLock(1200);
//        //三个参数 获取锁最大等待时间（期间会重试），锁的施放时间，时间单位
//        boolean isLock = lock.tryLock();
//        //判断是否获取锁成功
//        if (!isLock) {
//            //获取锁失败 返回错误或重试
//            //单人能请求能高并发，则直接提示错误，不用让他重试了
//            return Result.fail("一人只允许下一单");
//        }
//
//        //查询订单
////        synchronized (userId.toString().intern()) {
//        try{
//            //获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }finally {
//            //释放锁
//            lock.unlock();
//        }
////            return voucherOrderServiceImpl.createVoucherOrder(voucherId);
//
////        }
//    }
//    @Autowired
//    private VoucherOrderServiceImpl voucherOrderServiceImpl;
//
//voucherOrderServiceImpl.createOrder(voucherId);



}

